package io.trygvis.android.bt;

import android.bluetooth.BluetoothGatt;
import android.bluetooth.BluetoothGattCallback;
import android.bluetooth.BluetoothGattCharacteristic;
import android.bluetooth.BluetoothGattDescriptor;
import android.util.Log;

import java.util.ArrayDeque;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Queue;

import io.trygvis.android.F2;
import io.trygvis.android.Function;

import static io.trygvis.android.bt.BtActionExecutor.EventType.onCharacteristicChanged;
import static io.trygvis.android.bt.BtActionExecutor.EventType.onCharacteristicRead;
import static io.trygvis.android.bt.BtActionExecutor.EventType.onCharacteristicWrite;
import static io.trygvis.android.bt.BtActionExecutor.EventType.onConnectionStateChange;
import static io.trygvis.android.bt.BtActionExecutor.EventType.onDescriptorRead;
import static io.trygvis.android.bt.BtActionExecutor.EventType.onDescriptorWrite;
import static io.trygvis.android.bt.BtActionExecutor.EventType.onFailure;
import static io.trygvis.android.bt.BtActionExecutor.EventType.onFinally;
import static io.trygvis.android.bt.BtActionExecutor.EventType.onReliableWriteCompleted;
import static io.trygvis.android.bt.BtActionExecutor.EventType.onServicesDiscovered;

public class BtActionExecutor {
    private final static String TAG = BtActionExecutor.class.getSimpleName();
    private final Queue<BtCallback> actionQ = new ArrayDeque<>();
    private final Queue<BtCallback> failureQ = new ArrayDeque<>();
    private final Queue<BtCallback> finallyQ = new ArrayDeque<>();

    public synchronized BtActionExecutor onConnectionStateChange(F2<BluetoothGatt, Integer, Boolean> callback) {
        actionQ.add(new BtCallback("onConnectionStateChange") {
            @Override
            public boolean onConnectionStateChange(BluetoothGatt gatt, int newState) {
                return callback.apply(gatt, newState);
            }
        });
        return this;
    }

    public synchronized BtActionExecutor onServicesDiscovered(Function<BluetoothGatt, Boolean> callback) {
        actionQ.add(new BtCallback("onServicesDiscovered") {
            @Override
            public boolean onServicesDiscovered(BluetoothGatt gatt) {
                return callback.apply(gatt);
            }
        });
        return this;
    }

    public synchronized BtActionExecutor onCharacteristicRead(F2<BluetoothGatt, BluetoothGattCharacteristic, Boolean> callback) {
        actionQ.add(new BtCallback("onCharacteristicRead") {
            @Override
            public boolean onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
                return callback.apply(gatt, characteristic);
            }
        });
        return this;
    }

    public synchronized BtActionExecutor onCharacteristicWrite(F2<BluetoothGatt, BluetoothGattCharacteristic, Boolean> callback) {
        actionQ.add(new BtCallback("onCharacteristicWrite") {
            @Override
            public boolean onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
                return callback.apply(gatt, characteristic);
            }
        });
        return this;
    }

    public synchronized BtActionExecutor onCharacteristicChanged(F2<BluetoothGatt, BluetoothGattCharacteristic, Boolean> callback) {
        actionQ.add(new BtCallback("onCharacteristicChanged") {
            @Override
            public boolean onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
                return callback.apply(gatt, characteristic);
            }
        });
        return this;
    }

    public synchronized BtActionExecutor onDescriptorRead(F2<BluetoothGatt, BluetoothGattDescriptor, Boolean> callback) {
        actionQ.add(new BtCallback("onDescriptorRead") {
            @Override
            public boolean onDescriptorRead(BluetoothGatt gatt, BluetoothGattDescriptor descriptor) {
                return callback.apply(gatt, descriptor);
            }
        });
        return this;
    }

    public synchronized BtActionExecutor onDescriptorWrite(F2<BluetoothGatt, BluetoothGattDescriptor, Boolean> callback) {
        actionQ.add(new BtCallback("onDescriptorWrite") {
            @Override
            public boolean onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor) {
                return callback.apply(gatt, descriptor);
            }
        });
        return this;
    }

    public synchronized BtActionExecutor onReliableWriteCompleted(Function<BluetoothGatt, Boolean> callback) {
        actionQ.add(new BtCallback("onReliableWriteCompleted") {
            @Override
            public boolean onReliableWriteCompleted(BluetoothGatt gatt) {
                return callback.apply(gatt);
            }
        });
        return this;
    }

    public synchronized BtActionExecutor onReadRemoteRssi(F2<BluetoothGatt, Integer, Boolean> callback) {
        actionQ.add(new BtCallback("onReadRemoteRssi") {
            @Override
            public boolean onReadRemoteRssi(BluetoothGatt gatt, int rssi) {
                return callback.apply(gatt, rssi);
            }
        });
        return this;
    }

    public synchronized BtActionExecutor onFailure(Runnable callback) {
        failureQ.add(new BtCallback("onFailure") {
            @Override
            public void onFailure() {
                callback.run();
            }
        });
        return this;
    }

    public synchronized BtActionExecutor onFinally(Runnable callback) {
        finallyQ.add(new BtCallback("finally") {
            @Override
            public void onFinally() {
                callback.run();
            }
        });
        return this;
    }

    public String toString() {
        StringBuilder s = new StringBuilder("Queue: ");

        Iterator<BtCallback> it = actionQ.iterator();

        int i = 0;
        while (it.hasNext()) {
            BtCallback c = it.next();
            if (i > 0) {
                s.append(", ");
            }
            s.append(c.name);
            i++;
        }

        return s.toString();
    }

    public BluetoothGattCallback asCallback() {
        return new MyBluetoothGattCallback();
    }

    enum EventType {
        onConnectionStateChange,
        onServicesDiscovered,
        onCharacteristicRead,
        onCharacteristicWrite,
        onCharacteristicChanged,
        onDescriptorRead,
        onDescriptorWrite,
        onReliableWriteCompleted,

        onReadRemoteRssi,

        onFailure,
        onFinally,
    }

    private static Boolean callCallback(EventType key, BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, BluetoothGattDescriptor descriptor, int newState, BtCallback btCallback) {
        switch (key) {
            case onConnectionStateChange:
                return btCallback.onConnectionStateChange(gatt, newState);
            case onServicesDiscovered:
                return btCallback.onServicesDiscovered(gatt);
            case onCharacteristicRead:
                return btCallback.onCharacteristicRead(gatt, characteristic);
            case onCharacteristicWrite:
                return btCallback.onCharacteristicWrite(gatt, characteristic);
            case onCharacteristicChanged:
                return btCallback.onCharacteristicChanged(gatt, characteristic);
            case onDescriptorRead:
                return btCallback.onDescriptorRead(gatt, descriptor);
            case onDescriptorWrite:
                return btCallback.onDescriptorWrite(gatt, descriptor);
            case onReliableWriteCompleted:
                return btCallback.onReliableWriteCompleted(gatt);

            case onFailure:
                btCallback.onFailure();
                return null;
            case onFinally:
                btCallback.onFinally();
                return null;
            default:
                Log.w(TAG, "Unknown callback: " + key);
                return null;
        }
    }

    private class MyBluetoothGattCallback extends BluetoothGattCallback {

        private Queue<BtCallback> initialActionQ = new ArrayDeque<>(actionQ);
        private List<String> events = new ArrayList<>();

        void onEvent(EventType key, String values, BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, BluetoothGattDescriptor descriptor, int status, int newState) {
            boolean success = status == BluetoothGatt.GATT_SUCCESS;
            events.add(key + ", " + values + ", success=" + success);

            Log.i(TAG, "Operation failed: " + key + ", " + values + ", success=" + success);

            if (!success) {
                doFailure();
                return;
            }

            BtCallback btCallback;
            synchronized (this) {
                if (actionQ.isEmpty()) {
                    Log.d(TAG, "All Bluetooth actions are done");

                    doFinally();
                    return;
                }

                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    // ignore
                }
                btCallback = actionQ.remove();
                Log.i(TAG, "Executing bt action: " + btCallback.name);
            }

            try {
                boolean ok = callCallback(key, gatt, characteristic, descriptor, newState, btCallback);

                if (!ok) {
                    Log.w(TAG, "The callback don't want to continue.");
                    doFinally();
                }

                if (actionQ.isEmpty()) {
                    Log.i(TAG, "The queue is empty");
                }
            } catch (NotOverriddenException e) {
                Log.w(TAG, "Unexpected callback by listener: " + key);
                doFailure();
            }
        }

        private void doFailure() {
            StringBuilder msg = new StringBuilder();

            msg.append("Expected events: \n");
            for (BtCallback cb : initialActionQ) {
                msg.append("  ").append(cb.name).append("\n");
            }

            msg.append("Actual events: \n");
            for (String event : events) {
                msg.append("  ").append(event).append("\n");
            }

            Log.w(TAG, msg.toString());

            Log.w(TAG, "Executing " + failureQ.size() + " failure handlers");

            for (BtCallback callback = failureQ.poll(); callback != null; callback = failureQ.poll()) {
                try {
                    callCallback(onFailure, null, null, null, 0, callback);
                } catch (NotOverriddenException e) {
                    return;
                }
            }

            doFinally();
        }

        private void doFinally() {
            actionQ.clear();

            Log.w(TAG, "Executing " + finallyQ.size() + " finally handlers");

            for (BtCallback callback = finallyQ.poll(); callback != null; callback = finallyQ.poll()) {
                try {
                    callCallback(onFinally, null, null, null, 0, callback);
                } catch (NotOverriddenException e) {
                    return;
                }
            }
        }

        // -----------------------------------------------------------------------
        //
        // -----------------------------------------------------------------------

        @Override
        public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
            onEvent(onConnectionStateChange, "status=" + status + ", newState=" + newState, gatt, null, null, status, newState);
        }

        @Override
        public void onServicesDiscovered(BluetoothGatt gatt, int status) {
            onEvent(onServicesDiscovered, "status=" + status, gatt, null, null, status, 9);
        }

        @Override
        public void onCharacteristicRead(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
            onEvent(onCharacteristicRead, "status=" + status + ", characteristic=" + characteristic.getUuid(), gatt, characteristic, null, status, 0);
        }

        @Override
        public void onCharacteristicWrite(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic, int status) {
            onEvent(onCharacteristicWrite, "status=" + status + ", characteristic=" + characteristic.getUuid(), gatt, characteristic, null, status, 0);
        }

        @Override
        public void onCharacteristicChanged(BluetoothGatt gatt, BluetoothGattCharacteristic characteristic) {
            onEvent(onCharacteristicChanged, "characteristic=" + characteristic.getUuid(), gatt, characteristic, null, BluetoothGatt.GATT_SUCCESS, 0);
        }

        @Override
        public void onDescriptorRead(BluetoothGatt gatt, BluetoothGattDescriptor descriptor, int status) {
            onEvent(onDescriptorRead, "status=" + status + ", descriptor=" + descriptor.getUuid(), gatt, null, descriptor, status, 0);
        }

        @Override
        public void onDescriptorWrite(BluetoothGatt gatt, BluetoothGattDescriptor descriptor, int status) {
            onEvent(onDescriptorWrite, "status=" + status + ", descriptor=" + descriptor.getUuid(), gatt, null, descriptor, status, 0);
        }

        @Override
        public void onReliableWriteCompleted(BluetoothGatt gatt, int status) {
            onEvent(onReliableWriteCompleted, "status=" + status, gatt, null, null, status, 0);
        }

        @Override
        public void onReadRemoteRssi(BluetoothGatt gatt, int rssi, int status) {
//                onEvent(onReadRemoteRssi, "status=" + status, gatt, null, null, status, 0);
        }
    }
}